It was literally raining insect poop along much of the Grafton Loop Trail this weekend.

Honest!

Hiking up Puzzle Mountain on Saturday I stopped to rest. And that's when I first heard it.

The sound of rain.

But it couldn't be because the sun was out and the sky was bright blue.

I waited, listened some more, looked up, and realized that what I was hearing were insects eating away the leaves of the hardwood trees and dropping poop all over the place, and occasionally dropping themselves onto the forest floor.

I couldn't identify the beasty little critters who were making all the racket, but I finally did get a photo of one.

The Saddled Prominent caterpillar caught on a blue blaze along the Grafton Loop Trail.

Charlene Donahue, an entomologist with the Maine Forest Service, knew what it was right away when I called her yesterday: The Saddled Prominent.

According to Donahue, the Saddled Prominent is native to Maine and feeds on hardwood leaves, primarily beech, maple and oak. There's a surge in population every 8 years or so affecting mostly western Maine.

She couldn't say exactly what caused the periodic uptick in numbers, but figured weather might be a factor. The current outbreak is considered mild and should last another season or so before dying out again.

So the next time you hear rain in the woods and the sun is out, it might just be the Saddled Prominent. Who knew?

Now I'm gonna go clean the caterpillar crap off my backpack, thank you very much.